They enjoyed picture last evening.
They enjoyed themselves during summer vacation.
Enjoy is one of the verbs which takes reflexive pronoun with it when required. Reflexive pronoun is used when the subject of the verb is the received if the action. So in the first sentence why we haven't used reflexive pronoun with enjoy?
Best Answer
To enjoy oneself means to have a good time. When we use the verb ENJOY like this we don't mention the thing that gave us the feeling of enjoyment. The Object of the verb is the reflexive pronoun.
When we mention the thing that gives us the feeling of enjoyment, that thing becomes the grammatical Object of the verb. So if a film gave you a feeling of enjoyment, you can say I enjoyed that film. We don't use the reflexive pronoun when enjoy is used like this.
In the Original Poster's first example, we mention the thing that gave us the feeling of enjoyment. It's the picture. We don't need a reflexive pronoun here. In the second example, the speaker is just saying that we had a good time. He doesn't mention the thing that gave us the feeling of enjoyment, so we need a reflexive pronoun here.